How i can be 100 % sure that my computer work before the installation?
I tried NetBSD 5.1 (livecd) and the keyboard stop to function when i'm on the prompt. So i can't use it at all.
Yesterday i tried even OpenBSD 5.0 (livecd) and seem ok.
Which information - and using which command from the livecd - i must give you for be 100 % sure that everything work even after a real installation?
If everything is ok i will remove one linux distro from my system so i can give an all disk at openbsd (6gb of an old disk ...).

It was recently brought to my attention that because WiFi connections are not automated in my scripts, this may be an issue for those new to the OS. Wired Ethernet connections are automated, as long as the connection is physically made before booting.

To enable a WiFi, DHCP connection:

1. Discover the name of the attached WiFi NIC driver:

$ ifconfig

This will list all of the network interfaces, including pseudo devices like lo0 and pflog0. If you have both wired and wireless NICs, look for a NIC with an associated "nwid" field -- the SSID.

You can route the output of those commands to filesystems on USB or diskette, if that is easier than writing them out by hand. See OpenBSD FAQ 4.16 for an example of capturing a dmesg from the bsd.rd ramdisk installer, which would be similar.

Mounting these filesystems if defined via MBR is fairly easy. Step 1 - use disklabel(8) to determine what partition letters have been assigned to the partitions. IDE drives are wd0, wd1, wd2... and SCSI/USB/SATA drives are sd0, sd1, sd2... For example:

# disklabel sd2

That will produce a report of the partition letters assigned by OpenBSD (virtually) for the third SCSI/USB/SATA drive. Foreign filesystems with MBR partitions will be assigned letters between "i" and "p". Partition "c" is reserved, and is always the entire drive.

2. At the "(i)nstall, (u)pgrade, or (s)hell" prompt, type "s" and press Enter.

3. # ifconfig re0

---

If the output from ifconfig looks the same, then the problem still exists. If, however,
you now show a connected Ethernet (and perhaps better than 10mbps/half-duplex), you may check to see if you can obtain a network connection:

4. # dhclient re0

-current is now about a week or two in development beyond what will be 5.1-release, expected to be available on or about 1 May 2012.

I finally found the issue!
If, after the shell, i take the output from the command
# ifconfig re0
before run
# dhclient re0
the network give that strange result while if i take it after the run of the dhclient, i obtain the correct output.
So I asked myself, why not do a new test with the livecd 5 - i used the fluxbox image - but, this time, forcing the launch of the dhclient after i already inside of fluxbox, despite, this time, everything should be automatic.
And it is work!
So, in the end, the issue seem inside the livecd, where strangely the dhclient seem don't be launched during the boot.

Note
Now i' m writing from the inside of the livecd openbsd 5.
Using the follow command from inside the livecd
# wsconsctl keyboard.encoding=it
keyboard.encoding -> it
don' t give the change so was more difficult write the things, i have made some copy and past on some letters.